Industrial truck



July 4, 1950 A. w. GUNNING I INDUSTRIAL TRUCK 3 She'ets-Sheet 1 FiledJune 5, 1947 fizz/8226a".-

y 1950 A. w. GUNNING ,5 ,052

INDUSTRIAL mucx Filed June 5, .1947 3 Sheets-Shasta 2 y 1950 A. w.GUNNING 2,514,052

INDUSTRIAL 'mucx Filed June 5, 1947 3 Sheets-Sheet 3 as an IIIIIIIII InV612 ivr flyred Wgy/w Gunru'gy,

Patented July 4, 1950 INDUSTRIAL TRUCK Alfred Wayne Gunning, BattleCreek, Mich., as-

signor to Clark E chanan, Mich.,

quipment Company, Bua corporation of Michigan Application June 5, 1947,Serial No. 752,593

4 Claims.

This invention relatesto industrial trucks and more particularly isdirected to an improved load raising and supporting mechanism forindustrial trucks of the well known fork type.

In the majority of industrial trucks of the fork type now in use, therehas been encountered much difliculty in operations where the truck mustpass through a low doorway in going from one section of a warehouse toanother, or in carrying goods into a box car or the like where there islow overhead clearance, inasmuch as in most trucks of this type, theelevating mechanism, which carries 'the load supporting carriage, ofnecessity begins to extend upwardly as soon as the load is lifted, andeven in a carrying position projects to a point where it cannot clearcertain types of car doors and certain types of door openings withinwarehouses or mercantile buildings.

It is a primary object of the present invention to provide an industrialtruck wherein the load supporting carriage can be raised'to the fullextent of the stationary uprights before the inner or telescopinguprights begin to raise. With this construction, it is possible to pickup and carry loads through doorways having no more overhead clearancethan the vertical extent of the uprights or mast when in loweredposition, and to maneuver and dispose material within the door of a boxcar or in buildings with low overhead height without the'necessity ofincreasing the vertical height of the upright structure.

More specifically, the present invention involves an improved uprightand lifting arrangement whereby the forks of the machine can be raisedup to a height suilicient for tiering two stacks of material without thenecessity of increasing the overhead height of the machine, and whichwill still allow for very high lifting when there is no overheadobstruction.

For example, in one model of truck equipped with the present design, itis possible, with an upright structure having an over-all height of 83"collapsed position, to lift the fingers from ground level to 63" abovethe ground prior to any increase in the overall height of the uprightstructure. With this same structure, a maximum lift height of 130" canbe obtained when the mast structure is fully extended.

The present invention contemplates accompli shing these objects by theprovision of a three to one lifting ratio between the horizontalcylinder and the load supporting carriage. The design is such that theinner slides do not move vertically until the load supporting carriagehas reached a position substantially at the top of the stationaryuprights. From then on, the carriage does not move relative to the innerup- I rights but moves conjointly therewith as the inner uprights aretelescoped upwardly relative the stationary uprights.

The present construction has several additional advantages in that thehorizontal cylinder is reduced in length, thereby allowing the operatormore vision forwardly between the uprights above the cylinder when hemoves into position to pick up a load or the like.

Another advantage secured by the present invention is the provision ofmeans for insuring that the load supporting carriage when moved from itsextreme upper height downwardly, will not move relative to the innerslides, but will first move the inner slides downwardly therewith untilthe inner slides are fully telescoped into the stationary uprights. Atthis point, th mechanism is so designed that the carriage can then movedownwardly relative to the inner slides to its lowermost position at thebottom of the stationary uprights. This is accomplished by means of anovel latching mechanism consisting of a 2 way latch operating betweenthe upper end of the stationary uprights and the upper end of thetelescoping uprights. The latch is controlled by the movement of thetelescoping uprights and the load supporting carriage.

Other objects and advantages of the present invention will appear morefully from the following detailed description which, taken inconjunction with the accompanying drawings, will disclose to thoseskilled in the art, the particular construction and operation of apreferred form of the present invention.

In the drawings:

Figure 1 is a top plan view of an industrial truck embodying the presentinvention.

Figure 2 is a side elevational view of the truck shown in Figure 1 withthe upright structure shown in its raised position by dotted lines.

Figure 3 is a perspective view of the upright structure in its loweredposition.

Figure 4 is a corresponding view of the upright structure in fullyraised position.

Figure 5 is a detailed perspective view showing the latching mechanismbetween the load supporting carriage and the inner slides; and

Figure 6 is a diagrammatic view of the chain or cable arrangement foreffecting the lifting action. V

' Referring now in detail to the drawings, an industrial truck of anywell-known type is generally indicated at 5 and includes the body 6, thedriv- 3 ing wheels I, the steering wheels I and the rear counterweightl.

A driver seat is indicated generally at ll. adiacent the steering columni2, and the various controls for forward and reverse drive of thevehicle are indicated at [3.

The control mechanism for the lifting and tilting action of the uprightsis actuated by control levers i4, mounted above the engine compartmentadjacent the driver seat.

The upright construction generally comprises a pair of pivotally mountedstationary uprights II, which preferably adjacent their lower ends arepivotaily supported for forward and rearward tilting. These uprightspreferably comprise channel members maintained in laterally spacedrelationship at their lower ends by a suitable cradle member whichsupports the base end of the horizontal lift cylinder it, and at theupper end by the cross member II which may be welded or bolted to theouter sides of the channels l5 and extends rearwardly therebetween.

Disposed within the main uprights I! are a pair of secondary uprights orinner slides it which also preferably comprise channel members mountedin facing relation and guided on suitable wear strips I! for slidingmovement vertically within the channels ii. The channels it, at theirupper ends, are secured together by means of a cross member 20, whichcross member is provided with a depending flanged portion 22, shown morein detail in Figure 3, carrying brackets 23, upon which are mountedrotatable sprockets.

Adjacent their lower ends, the outer stationary uprights I! are providedwith brackets 24 which are connected to the extending ends of pistonrods 25 to provide for forward and reverse tilting action of the entiremast structure about the pivotal mounting of the uprights ii.

The cylinder ii is provided with a piston disposed therein and havingthe extending piston rod 28, which, at its upper end, terminates in acrosshead 21, carrying sprockets at each side thereof, indicatedgenerally at 28. Mounted on the uprights l5 between the bracket 24 andthe upper cross member I1, is a transverse bracket II, which bracketcarries suitable sprocket members 32, disposed in substantially the sameplane as the sprockets 28 of the crosshead 21. The inner slides it, atthei lower end, are also provided with a transverse spacing member 33,carrying sprockets 34 adjacent each side thereof, and also arranged insubstantially the same planes as the sprockets 28 and 32.

In the construction thus far. described. suitable chain means areanchored on the crosshead 21, as indicated at the anchoring points 35,in Figure 5, and thence extend downwardly and are trained about thestationary sprockets 32, carried by the bracket 30, fixed to the rear ofthe stationary uprights. This portion of the chain means is indicated byreference numerals 36. The chains are then trained about the sprocketsand vertically upwardly over the sprockets 28 carried by the crosshead21. This portion of the chain means is indicated by the referencenumerals 31. After leaving the sprocket 28, the chain means extendsdownwardly within the inner uprights l8 to the sprockets 34, carried atthe lower end of the uprights it and secured in position by thetransverse bracket 33. This run of the chain means is indicated by thereference numerals 38.

After being trained around the sprockets 34,

. 4 i the chain means extends vertically from the lower end of the inneruprights II to the upper end thereof, and is trained over the sprocketscarried by the bracket 23 on the cross plate 22. This run of the chainis indicated by reference numerals 33, and it will be noted that in theposition shown in Figure 3, there is provided a right angle link 4| inthis run ofthe chain inasmuch as the sprockets carried by 'thebrackets23 are disposed at right angles relative to the planes of the sprockets23, 32 and 34. The chain again extends downwardly between the two runs38, and, at its lower end, is anchored to the load supporting carriage,indicated generally by the reference numeral 42. This load supportingcarriage, as will be more apparent mm 1, 2 and 5, comprises a bodymember extending forwardly of the uprights l3 and having verticallyspaced face plates 43 and 44 upon which are mounted L shaped liftfingers, indicated generally at 4!. The body member 42 also hasa-rearwardly extending bracket portion on each side thereof, whichextends inwardly between the uprights and is adapted to carry suitableroller members engaging the flanged faces of the inner channels it,whereby the carriage is guided for vertical movement relative to theinner slides and may roll upwardly and downwardly therein.

These bracket portions are indicated at 40 in Figure 5 and extendsubstantially across the face of the inner uprights it on opposite sidesof the crosshead 21 and its associated sprockets 23.

The operation of this lifting mechanism will be more apparent from anexamination of the diagrammatic showing in Figure 6 of the drawings, inwhich the structural portions of the mechanism have been eliminated toshow the movement of the chaidmechanism during the raising and loweringoperations. The sprocket wheels have been given the same identifyingnumerals in this figure, and the upper sprockets carried by the bracket23 at the upper ends of the inner slides II, have been identified at23'.

The position of the mechanism in the diagrammatic showing at A shows theforks 45 in lowermost position and with the other parts of the mechanismapproximately in the position shown in Figure 3.

As the hydraulic pressure within the lift cylinder It acts to extend thepiston 2i vertically, the sprockets 28 move upwardly being carried onthe end of the piston, andsince this upward movement produces a three toon ratio of movement of the lift forks, the position of the sprockets 28changes, while the position of the sprockets 23' and 34 remains the sameuntil such time as the forks are moved to the upper ends of the innerslides, which positionis shown at B in Figure 6.

It will be noted that during this movement, the piston has traveled thedistance indicated by the movements of the sprockets 28 and that thishas resulted in a complete raising of the forks 45 to the upper end ofthe inner slides carrying the sprockets 23'. The anchor sprockets 32have, of course, remained stationary, being fixed against movement, andthe inner slides having remained stationary, the sprockets 34 and 23'also have not moved.

As the piston is'further extended, the inner slides and the forks movevertically upwardly as a unit relative to the stationary mast l5, untilthey finally arrive at their uppermost position, indicated at C inFigure 6. It will be noted that while th fixed sprockets 32 are still inthe same position, the piston actuated sprockets 28 have moved upwardlyapproximately again as far as they moved in going from position A toposition B. However, this movement has resulted in almost a completeraising of the sprockets 34 and 23' to a position where the inneruprights it are fully extended except for that portion thereof necessaryto be maintained in the upper ends of the uprights ill for stabilizingpurposes.

Figure 2 of the drawings indicates diagrammatically the fork position atthe three shown at A, B, and C in Figure 6.

It will be apparent that by anchoring one end of the chain of themovable sprockets 28 and training it over the stationary sprockets 32, athree to one lifting ratio is provided so that the forks are raisedthree inches for every inch of extension of the piston. As a result,since the piston and cylinder in collapsed position are approximatelyonly of the height of the stationary uprights I5, the movement of thepiston into a position at the upper end of the uprights I5 results inraising the load supporting carriage up into a position substantially inthe upper ends of the stationary uprights. Further movement of thecarriage 42 relative to the inner slides is, of course, not possible inthis fully raised position, and consequently from this time on, thecarriage 42 moves conlointly with the inner slides vertically out of thestationary supporting uprights l5.

Another movement of the piston head of approximately of the length ofthe inner slides raises the inner slides to their fully extendedposition, again because of the three to one lifting ratio.

In a mechanism of this type, it is highly desirable that the innerslides be prevented from moving vertically until such time as the loadsupporting carriage has reached the upper end of the inner slides. It isfurther highly important that when being lowered from the fully raisedposition, such as indicated at C in Figures 2 and 6, that the innerslides move downwardly conjointly with the load supporting carriage, inorder to prevent the carriage moving relative to these slides. untilafter the slides have again been nested completely within the stationaryslides l5. For this reason, a latching mechanism has been developedwhich is shown most clearly in Figure 5, for con-- trolling the relationof movement of the inner slides relative to the load supporting carriageand to the stationary uprights under the .various conditions outlinedabove.

This latch mechanism briefly comprises the brackets 50 mounted on therear flange of the slides ll adjacent their'upper ends and carrying aT-shaped latch member 52, which is pivotally mounted thereon and whichpreferably has a depending latch carrying arm and normally extendingactuating arms. The latch portion of the members 52, comprises adepending arm 53, carrying oppositely projecting latch detents 54 and55, respectively. The latch detent 55 is adapted to have latchingengagement with a latch dog 56, mounted on each of the brackets 46 ofthe body portion of the load supporting carriage 42. The opposite detent54 of the arms 53 is adapted to have latching engagement with suitablelatch dogs 51, carried on the inner surface of the cross member ll,permanently secured to the upper end of the stationary uprights l5.

Suitable spring mounted control buttons or plungers 58 are provided inthe flanged portion of the member I1 and are adapted to be engaged bythe cam portions 59 of the latch members 52 points latches are thusengaged with the dogs 51, the

inner uprights cannot move vertically and the load supporting carriage,of course, then traverses the vertical extent of the uprights ll, movinginto the position shown in Figure 5.

As it moves into this position, the upper ends of the brackets 46 havesuitable surfaces adapted v to engage cam surfaces 8|, formed on thelatches 52, which rock these latches out of engagement with the dogs 51,thereby allowing. the inner uprights II to be released from lockedengagement with the outer uprights and allowing the inner slides to thenmove upwardly coniointly with the load supporting carriage 42.

When the mechanism has reached'its uppermost position, however, and itis desired to lower the forks 45, initial lowering movement brings thedogs tents 55, thereby locking the load supporting carriage 42 securelyto the uprights it, so that the carriage and the uprights must movedownwardly in conjoint relation. They thus move downwardly to a pointslightly below the position shown in Figure 5, at which time, thelatches have the cam surfaces 59 thereof, engage the buttons 5|, therebyrocking the latches out of engagement with the dogs 58 and releasing theload supporting carriage for further load lowering movement.

In normal operation of the mechanism thus far described, it has beenfound that the load supporting carriage will travel to the upper end ofthe inneruprights l8 before these uprights besin to move, primarilybecause of the fact that a the uprights are held against movement by therelationship of the sprockets at opposite ends thereof, over which thelift chains are trained. It has also been found that in moving fromuppermost position 0, downwardly, the load supporting carriage has a.tendency to stay at the upper ends ofthe uprights I I, so that it movesdownwardly conjointly with the uprights until the uprights bottom intheir collapsed position at which time the forks continue their downwardmovement.

However, it is desirable that the latch mechanism be provided to insurethis proper sequence of movement, and the simplified type ofconstruction herein disclosed provides for positive locking of theuprights in the manner described.

It is therefore believed apparent that the present invention provides anovel type of lifting arrangement, whereby the load supporting carriagecan be lifted substantially to the upper end of the stationary uprightsbefore the overall height of the lift mechanism is increased and thusfacilitate the picking up and transporting of loads through low.doorways or into box cars or the like, without increasing the mastheight. This also allows for tiering up to two loads, one on top of theother, without the necessity for increasing the overall height of themachine. The latch mechanism, of course, provides a safety factor toinsure the proper sequential movement of the lift mechanism.

I am aware that various changes may be made in certain details of thepresent construction without in any way departing fr m the underly- 56into engagement with the latch de- 7 ing principles of the presentinvention, and I therefore do not intend to be limited except as definedby the scope and spirit of the appended claims.

I claim:

1. In an industrial truck having a vertical mast at one end thereof,telescoping members guided for vertical movement in said mast, a loadsupporting carriage guided for vertical movement in said telescopingmembers, raising means carried by said mast for initially raising saidcarriage to the upper end of said telescoping members and for thenraising said members and carriage conjointly relative to said mast, andlatch members at the upper end of said telescoping members normallyholding said members against raising movement relative to said mast,including means on said carriage operable when in raised positionrelative to said telescoping members for disengaging said latch membersfrom said mast and for locking said carriage and telescoping membersior'conjoint movement.

2. In an elevating mast for an industrial truck having a fixed mast, atelescoping inner mast guided therein, and a load-supporting carriageguided in said inner mast, an extendible cross head insaid masts, aflexible member received between said most and cross head and operableupon extension of said cross head for first raising said carriage to theupper end of said inner movement.

8 3. In an elevating mast for an industrial truck having a fixed mast, atelescoping inner mast guided therein, and a load-supporting carriageguided in said inner mast, an extendible cross head in said masts, aflexible member received between said masts and cross head and operableupon extension of said cross head for first raising said carriage to theupper end of said inner mast, and thereafter conjointly raising saidinner mast and carriage within said fixed mast, and latch meansoperative to lock said carriage and inner mast against relative movementwhenever said carriage is at the upper end of said inner mast and saidinner mast is not bottomed in said fixed mast.

4. In an elevating mast for an industrial truck having a fixed mast, atelescoping inner mast guided therein, and a load-supporting carriageguided in said inner mast, an extendible cross head in said masts, aflexible member received between said masts and cross head and operableupon extension of said cross head for first raising said carriage to theupper end or said inner mast, and thereafter coniointly raising saidinner mast and carriage within said fixed mast, and T-shaped latch meanspivoted at the upper end of said inner mast selectively operable to locksaid inner mast against relative telescoping movement or to lock saidcarriage and said inner mast against relative movement.

ALFRED WAYNE GUNNING.

' REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number -Name Date 1,900,195 Butterworth Mar. '7,1933 2,261,930 Abbe Nov. 11, 1941

